The invention relates to a method and apparatus for balancing the unbalance of rotational bodies, wherein the measured values are ascertained and processed by means of electro-mechanical measuring transducers, reference signal generators, and multiplication devices.
In prior art balancing methods it is usual to ascertain the unbalance electrically in two measuring planes. The forces caused by the unbalance are transmitted to the bearings of the rotating body to be balanced and respective unbalance signals are evaluated and processed by electrical means. Load cells, displacement pick-up means, and speed transducers may be used for ascertaining the unbalance values which will be referred to hereafter as measured signals or values. The measured signals provided by the detectors or transducers normally comprise in addition to the unbalance information a mixture of oscillations. These measured signals are processed in analog electrical circuits. Such analog measured signal processing normally provides values for the unbalance of the body being tested by indicating the size and angular position of the unbalance, or by indicating components thereof, mostly in two measuring planes. The unbalance values, or rather the signals representing the unbalance values may be transmitted relative to correction planes through the rotor, they may be indicated, registered and held ready for further processing or for controlling the unbalance correction. The correction is normally accomplished by the balancing machine, which automatically starts and controls the correction procedure.
Conventional balancing methods operate relatively slowly especially if complicated balancing problems are to be solved and if a high precision in the balancing must be maintained. Thus, prior art balancing methods may require a substantial length of time for permitting the balancing. Substantial and complicated balancing problems also require complicated electric circuits. The production of such circuits and their operation may involve errors which falsify the measured results or which may interfere with the testing sequence. Another drawback of analog balancing devices is seen in that it is not possible to directly connect these devices to a central data gathering and data processing system, for example, to control the mass production of rotors or the like.
German Patent Publication 1,298,735 discloses an apparatus wherein the working tools for the unbalance correction are controlled by a digital device. However, the unblance itself is ascertained and processed by analog means.